The structure and operation of conventional slug production devices for brick-making machines, as indicated in FIG. 1, mainly consists of placing the raw brick material into the filler trough (D), after which two horizontal and parallel mixing blades (2) in the mixer tube (1) rotate in opposite directions and moves the raw brick material mixture into the mixer tube (1) and, at the same time, the screw rod (3) at the front end of the mixing blades (2) conveys the raw brick material into the mixing tube (2), which is then pulverized into granules and conveyed by crushing blades (4) in the vacuum trough (E), and inside the aforesaid vacuum trough (E) are two more pressure blades (5) in a horizontal and parallel configuration that rotate in opposite directions, such that the raw brick mixture granules in the vacuum trough (E) are conveyed into the forming tube (6) positioned below and, furthermore, moved forward by the screw rod (7) and pushed out through the forming holes (8), enabling the forming holes (8) to shape the material into long slugs. Undeniably, the structure and operation of this kind of slug production device for brick-making machines offers practical value and functionality and, furthermore, virtually all current slug production devices for brick-making machines utilize such a design. However, following long-term utilization, manufacturers find that the aforesaid devices have numerous shortcomings that await improvement, including:
(1) Although the raw brick mixture in the forming tube (6) is driven forward smoothly by the screw rod (7) along the circumferential surface around the screw rod (7), the aforesaid circumferential surface is subject to straight, slanted or spiral abrasion marks from the friction blocks of the lining sleeve. However, a lining sleeve having numerous friction blocks gives rise to insllation difficulties and inconvenience as well as wastes time and effort, especially at the interface of the friction blocks and the screw rod (7), where rapid wear easily occurs due to the continuous friction from the passage of raw brick material, which consequently requires frequent disassembly and replacement that is highly inconvenient and uneconomical.
(2) Since the friction blocks are directly against the circumferential surface of the forming tube (6) and thereby increase the friction that generates straight, slanted and spiral abrasion marks, when the screw rod (7) drives the raw brick mixture forward, the driven raw mixture etches numerous flow marks that in turn produces backflow, which not only prevents the screw driven raw brick material from exiting from the forming hole (8) in the desired quantity, but also reduces raw brick material mixing efficiency. At the same time, when the raw brick material additionally scours the straight, slanted and rotary abrasion marks, the actual required force of friction provided is greatly diminished, which drastically lowers the driving efficiency of the screw rod (7).
(3) Since the raw brick material inside the forming tube (6) is propelled forward by the drive mechanism of the screw rod (7), a direct increase in load is produced. As such, in actual operation, the aforesaid drive mechanism not only requires increased horsepower, but also entails the consumption of more fuel and generation of intense noise and, especially in the case of the drive components, the additional increase in load directly results in rapid wear and a shortening of service life that is not economical.
(4) Since the raw brick material inside the forming tube (6) utilizes the combined friction from the rotation and friction blocks of the driving screw rod (7) to gradually flow out into formed raw brick slugs, the center flow speed and the peripheral flow speed of the aforesaid slugs differs (the center flows faster because the friction is less, while the periphery flows slower due to the effect of the friction blocks) and, furthermore, the slugs cannot be produced in equal density. Therefore, when the slugs are baked after final cutting, changes in shape, cracks and breakage tend to frequently occur.
(5) Since the aforesaid raw brick material is placed into the filler trough (D), after which the aforesaid material must pass through the two rotating mixer blades (2) to be transported into the mixer tube (1) and then two rotating screw rod s (3) further convey the aforesaid mixture into the vacuum trough (E), therefore, the required installation of the aforementioned friction blocks constitute a drawback, the results of which are fully evident.